Here, I am going to write what I understand and among the gems I obtained from it InshaAllah.

Lord of the worlds means that He is The Cherisher, The Sustainer, The Maintainer, The Caretaker, The owner of all worlds. It comes from the root word rabbaa(Ra’ Ba’ Ya’), which means to nourish, to educate. An educator brings his students from darkness to light. So, as a Rabba, which means the Sustainer, He sorts of sustains us in this world, provide for us, meet our every need. He also guides us.

So, Rabb Al-A’aalameen here means…

1) The Sustainer of all worlds

2) The Caretaker of all worlds

3) Guider of all creation

He is the greatest, greater than the whole great universe. Greater than all the universes combined. The sky we see up there and the outerspace beyond. All that is the first heave ns. There are 6 more heavens out there. And above them all, there is Allah’s A’rsh, translated as throne.

The Prophet ﷺ told us:

ما السماوات السبع في الكرسي ، إلا كحلقة ملقاة بأرض فلاة

“The seven heavens are no more in comparison to the Kursi than a ring thrown in a desert.” (Ibn Hajar)

If that is the Kursi, then what of the magnificent Throne?

He then said:

فضل العرش على الكرسي ، كفضل تلك الفلاة على تلك الحلقة

“And the superiority of the Throne over the Kursi is like that desert compared to that ring.”

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That is only the lowest heaven…

…and Allah is Akbar, the Greatest.

He knows what is in everyones hearts. since the creation of the first human, Adam Alayhi As-Salaam.

He says: Verily, Allah is Knowing of that within the breasts. (5:7)

He is forever(permanent, without start nor end) and we are only temporary with definitely a start and end.

Everyone knows Him, even the unbelievers. But who knows us?

He says:

Has there [not] come upon man a period of time when he was not a thing [even] mentioned? (76:1)

In prayer, as we read the first verse of Al-Fatihah, feel that HIs immense gaze is watching our hearts and He knows what we are thinking.